• Code: 391.914
• Description: Drum CRUM K Communication Fault. Communication failure with the Imaging Unit (K) CRUM was detected.
• Remedy: 1. Turn the power Off and On. 2. Turn the power Off and check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (K) P/J115 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (K) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (K) CRUM for damage and foreign substances • The Imaging Unit (K) CRUM PWB for contamination or disengagement • The Imaging Unit (K) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (K) • Imaging Unit CRUM Coupler Assembly (K) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.915
• Description: Drum CRUM K Data Broken. The system detected that the data written to the Imaging Unit (K) CRUM and the data read from the Imaging Unit (K) CRUM do not match.
• Remedy: Remove and reinstall the Imaging Unit (K) and check for improper installation. If no problems are found, replace the Imaging Unit (K).

• Code: 391.916
• Description: Drum CRUM K Data Mismatch. Incorrect authentication area data was detected in Imaging Unit (K) CRUM.
• Remedy: Remove and reinstall the Imaging Unit (K) and check for improper installation. If no problems are found, replace it with the correct the Imaging Unit (K).

• Code: 391.917
• Description: Drum CRUM Y Communication Fault. Communication failure with the Imaging Unit (Y) CRUM was detected.
• Remedy: 1. Turn the power Off and On. 2. Turn the power Off and check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (Y) P/J112 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (Y) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (Y) CRUM for damage and foreign substances • The Imaging Unit (Y) CRUM PWB for contamination or disengagement • The Imaging Unit (Y) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (Y) • Imaging Unit CRUM Coupler Assembly (Y) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.918
• Description: Drum CRUM M Communication Fault. Communication failure with Imaging Unit (M) CRUM was detected.
• Remedy: 1. Turn the power Off and On. 2. Turn the power Off and check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (M) P/J113 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (M) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (M) CRUM for damage and foreign substances • The Imaging Unit (M) CRUM PWB for contamination or disengagement • The Imaging Unit (M) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (M) • Imaging Unit CRUM Coupler Assembly (M) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.919
• Description: Drum CRUM C Communication Fault. Communication failure with Imaging Unit (C) CRUM was detected.
• Remedy: 1. Turn the power Off and On. 2. Turn the power Off and check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (C) P/J114 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (C) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (C) CRUM for damage and foreign substances • The Imaging Unit (C) CRUM PWB for contamination or disengagement • The Imaging Unit (C) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (C) • Imaging Unit CRUM Coupler Assembly (C) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.921
• Description: Drum CRUM K Not In Position. The Imaging Unit (K) CRUM is not in the proper position (loose CRUM).
• Remedy: 1. Remove and reinstall the Imaging Unit (K). 2. Polish the connection terminals between the Imaging Unit (K) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (K) CRUM with dry cloth. (When cleaning, do not use Imaging Unit cleaner, etc.) 3. Check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (K) P/J115 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (K) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (K) CRUM for damage and foreign substances • The Imaging Unit (K) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (K) • Imaging Unit CRUM Coupler Assembly (K) (PL 8.1) • MD PWB • MCU PWB

• Code: 391.927
• Description: Drum CRUM Y Not In Position. The Imaging Unit (Y) CRUM is not in the proper position (loose CRUM).
• Remedy: 1. Remove and reinstall the Imaging Unit (Y). 2. Polish the connection terminals between the Imaging Unit (Y) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (Y) CRUM with dry cloth. (When cleaning, do not use Imaging Unit cleaner, etc.) 3. Check the following: • The connection between the MD PWB P/J528 and the Imaging Unit CRUM Coupler Assembly (Y) P/J112 for open circuit, short circuit, and poor contact • The connection terminals between the Imaging Unit (Y) CRUM PWB and the Imaging Unit CRUM Coupler Assembly (Y) CRUM for damage and foreign substances • The Imaging Unit (Y) for improper installation If no problems are found, replace the following parts in sequence: • Imaging Unit (Y) • Imaging Unit CRUM Coupler Assembly (Y) (PL 8.1) • MD PWB • MCU PWB